[Using examples of firefly luciferase gene for the study of biological activities (estrogens, retinoids, phorbol...

Some possible applications of chimeric cellular models, specifically responding to an effector through firefly luciferase induction are presented with the help of examples in relation with the biological activity of estradiol or retinoic acid, or phorbol ester. A comparison of experiments on either chimeric or natural responses shows that: i) the responses of both type of cellular models are effector concentration-dependent; ii) these concentrations are in the same order of magnitude; partial agonist compounds and antagonist compounds; iv) potencies (EC50) of test-compounds are similarly classified. Moreover we show that a chimeric cellular model allows the observation of interactions between hormone or effector pathways: it allows readily performed kinetic studies and long-term experiments in intact cells that permit to investigate the effect of a given effector, its reversibility and time-dependent action. Therefore, various steps of a cellular signalling pathway involved in the action of an effector may be observed with such a valuable tool.